ndb.dip_iR_and_P fragments

[vamshi.katukuri]

Dear all,

I am trying to extract the dipole matrix elements for a particular set of bands. Going through the forum viewtopic.php?f=13&t=382&p=2621&hilit=dipole#p2621 , I understood that one can do that using the python script. However it seems to be for an older version of Yambo. Now I am trying to modify it to be compatible with the latest release. In Yambo 4.0.3 Revision 104, the ndb.dip_iR_and_P files are written in a separate folder (if -J option is used) outside the SAVE folder. Further the ndb.dip_iR_and_P is fragmented into several files, e.g, ndb.dip_iR_and_P_fragment_101. I am not able to understand how these fragments are connected and how one can combine all of them to get one ndb.dip_iR_and_P file. Any help will be appreciated.

Regards
Vamshi
PostDoc
Institute of Physics, EPF Lausanne

[Daniele Varsano]

Dear Vamshi,
yes, the script mentioned in the forum as you can see from the date of the post was quite old.

In Yambo 4.0.3 Revision 104, the ndb.dip_iR_and_P files are written in a separate folder (if -J option is used) outside the SAVE folder.

Ok, but this should not be a problem, you can copy, symlink or simply run without the -J option as you wish.

Further the ndb.dip_iR_and_P is fragmented into several files, e.g, ndb.dip_iR_and_P_fragment_101. I am not able to understand how these fragments are connected and how one can combine all of them to get one ndb.dip_iR_and_P file.

The number of the fragments are connected to the number of the K points, so you have a different file for any K point. If you want to avoid fragmentation you can try to add in your input file to add the line:

Code: Select all

DBsFRAGpm= "-DIP"  

pay attention to the minus sign. This variable appears when adding IO verbosity when building the input file "-V io". It should work but I never tried it.

If you update that python script and you will to share it, we will be happy to add it in the python yambo tool suite.

Best,
Daniele

[Davide Sangalli]

Dear Vamshi,
in the new ndb.dipoles the matrix elements DIP(3)_cvk\sigma are stored with the indexes running as follow
(first index run faster):
a) real, imaginary part
b) cartesian index (xyz)
c) conduction band index
d) valence band index
e) k-point index (if you fragment this index goes into the fragment index)
f) if n_sp_pol>1, spin index (if you fragment this index goes into the fragment index)

Hope it helps to upgrade the script.

Best,
D.